A common type of battery (electric cell) for consumer electronic equipment is cylindrical, with top and bottom battery terminals separated by more than the battery diameter. Perhaps the most common of this type of battery is the AA battery which has a diameter of 14 millimeters, a body length of 48 mm, and a length between the ends of its opposite terminals of 50 mm. AAA batteries are smaller, and have a diameter of 10.5 millimeters, a body length of 44.5 mm, and a length between the ends of its opposite terminals of about 47.0 mm. While the batteries used for electronic devices are relatively small, it is not convenient to carry spare batteries in one's pocket or elsewhere on the person since they create an annoyance, and such loosely held spares may be forgotten. Further, if a consumer carries loose batteries for replacing dead batteries, and then mixes the two, he/she cannot readily (without testing) tell whether or not the battery is charged or discharged.
Battery holders are available, and usually include a molded plastic case with multiple receptacles or divider-created slots for holding batteries so that they do not move around. The case lid, when closed, secures the batteries within the case (and often from rolling around), and when the lid is opened the batteries can easily be lifted out. For instance, a case-type battery storage box with dividers for different battery sizes can be seen at http://www.spacesavers.com/Storage/Battery-Storage/Multi-Size-Battery-Storage-Box-by-Dial. Boxes and cases have their merits, but don't permit rapid access to the batteries and are often formed of opaque plastic which prevents seeing how many batteries are left at a glance.
PowerPax of St. Charles, Ill. manufactures a line of battery holders or caddies under the StoraCell™ battery management systems name. The holders include cylindrical receptacles that are not fully enclosed so one can see the battery, each with one closed end and one end having one or more small cantilevered pawls that hold the battery in place. To remove a battery one must push on an end corner of the battery nearest the closed end so that the top end forces the cantilevered pawls apart.
Despite several designs of prior consumer battery holders, there remains a need for a one-piece, unitary holder that permits easier access to the batteries.